Nothing beats a warm, comforting bath after a long, tiring day. Except, perhaps, using your own homemade, natural bath products. That’s why today I’m going to show you how to make a simple blooming bath oil that will elevate your bath experience and make you feel like you’re at the spa.
This luxurious bath oil takes just 10 minutes to make and anyone can recreate it. In fact, you won’t believe how easy it is to make and how amazing it feels on the skin. And I just know you’ll fall in love with its “blooming” effect. When this oil touches water, it transforms into a silky, milky texture that deeply nourishes and moisturises your skin. Plus, it’s got a gorgeous floral scent and a stunning pink/red colour.
Whether you’re new to formulating or already a seasoned pro, this bath oil is the perfect way to treat yourself or surprise someone special. So let’s get right into it!
What is a bath oil?
A bath oil is a luxurious, moisturising product designed to be added to your warm bath water. It’s typically made from a blend of oils that help moisturise, nourish, and soothe the skin while providing a relaxing bath experience. I’ve added essential oils and colouring to mine for a more sensorial experience.
Why you’ll love this bath oil
This isn’t just any bath oil—it’s an experience for both your skin and senses. Here’s why you’ll love it:
- Changing texture: This bath oil transforms into a silky, milky solution the moment it hits the water, hence the “blooming” effect.
- Striking colour: The vibrant pink/red colour, derived from the gromwell plant, adds a fun and vibrant touch to your bath.
- Moisturising properties: This bath oil has amazing nourishing properties thanks to its plant oils, which leave your skin feeling moisturised.
- Relaxing scent: Bergamot, lavender and ylang-ylang essential oils pair together for a calming, floral fragrance – perfect for unwinding.
But best of all, this blooming bath oil is super easy and satisfying to make. It’s also fully customisable, as you’ll find out in the sections below.
Key ingredients
Before we dive into the formulation, let’s just take a moment to examine the key ingredients of this bath oil and discover what makes this bath oil so special.
Castor oil
INCI: Ricinus Communis Seed Oil
I’ve chosen castor oil for its amazing moisturising and skin-conditioning properties. This oil creates a silky, smooth texture that locks in moisture, leaving your skin soft and moisturised– perfect for a bath oil. Plus, it’s packed with ricinoleic acid, an omega-9 unsaturated fatty acid, which helps soothe and protect the skin. Learn more about castor oil below:
MCT
INCI: Caprylic/Capric Triglyceride
I’ve also used MCT in this bath oil for its fast-absorbing, lightweight texture that leaves your skin soft without feeling non-greasy. MCT is a triglyceride containing medium-chain fatty acids and can be produced by separating a fraction of coconut, palm or other oils. It can also be hydrogenated.
If you’d like to find out more about botanical oils, check out our Botanical Oils Mini Lab on our exclusive membership site, the Lab at Formula Botanica.
Plum oil
INCI: Prunus Domestica Seed Oil
Plum oil is one of my favourite ingredients in this bath oil. It’s a more precious botanical oil that adds an extra touch of luxury to this formulation. While I chose the other ingredients because I already had them in my formulation stash, plum oil was my special choice.
While I used larger amounts of MCT and castor oil to keep the formula budget-friendly, I wanted to add a unique and precious ingredient, so plum oil made the cut. This oil is rich in antioxidants, essential fatty acids, and vitamins, which nourish the skin while providing a subtle, delightful fragrance. If you’re interested in learning more about plum oil, I recommend you listen to this fascinating podcast episode:
PGMO.4
INCI: Polyglyceryl-4 Oleate
The star ingredient in this formulation is PGMO.4, a water-in-oil (w/o) emulsifier that makes this bath oil truly magical. It’s the key to the blooming effect: when the oil meets water, it turns into a silky, milky emulsion that disperses beautifully in your bath. This ensures the oils blend seamlessly with the water, creating a luxurious experience without leaving a greasy residue on your skin or bathtub.
You can learn more about emulsifiers in the blog posts below:
Everything you wanted to know about natural emulsifiers
Additional ingredients
Essential oils
INCI: Citrus Aurantium Bergamia Peel Oil/Lavandula Angustifolia Oil/Cananga Odorata Flower Oil
I’ve also added some essential oils to this oil to make it fragrant. I’ve selected a blend of bergamot, lavender, and ylang-ylang essential oils for their calming, floral aroma, perfect for creating a relaxing spa-like experience.
Gromwell extract
INCI: Helianthus Annuus Hybrid Oil, Simmondsia Chinensis Seed Oil, Lithospermum Erythrorhizon Root Extract
Gromwell extract is what gives this bath oil its natural pink-red colour. It adds a playful touch to the formulation, which can elevate your bath experience. To learn more about other plant-based colourants, check out this post:
Vitamin E
INCI: Tocopherol
Vitamin E is a powerful antioxidant that can help extend the shelf life of the oils and therefore of your product. It also has skin-conditioning properties, leaving your skin feeling nourished and soft after your bath.
You can learn more about antioxidants in our dedicated Antioxidants Mini Lab, at the Lab at Formula Botanica.
Formulation breakdown
This blooming bath oil is a nourishing treat that transforms into a silky, milky solution when it meets water. Just add a splash to your bath and get ready to relax!
Makes: 50g
Formulation: Cold-process
Time: 10-15 minutes
Level: Beginner-friendly
| Phase | Ingredients | INCI | Weight (g) |
| A | Castor oil | Ricinus Communis Seed Oil | 17.50 |
| A | Medium chain triglycerides (MCT) | Caprylic/Capric Triglyceride | 15.90 |
| A | PGMO.4 | Polyglyceryl-4 Oleate | 10.00 |
| A | Plum oil | Prunus Domestica Seed Oil | 5.00 |
| B | Bergamot essential oil | Citrus Aurantium Bergamia Peel Oil | 0.50 |
| B | Lavender essential oil | Lavandula Angustifolia Oil | 0.25 |
| B | Ylang-ylang essential oil | Cananga Odorata Flower Oil | 0.25 |
| B | Vitamin E | Tocopherol | 0.50 |
| C | Gromwell oil extract | Helianthus Annuus Hybrid Oil, Simmondsia Chinensis Seed Oil, Lithospermum Erythrorhizon Root Extract | 0.10 |
| Total: 50.00 |
Equipment:
- Scales
- Glass beaker
- Glass rod
- Stainless steel spoons
- Watch glass
- Pipettes
- Bottle
Our formulation: Make a blooming bath oil
Making this blooming bath oil is incredibly easy and takes just 10 minutes. Are you ready? Let’s get into it!
Step 1: Prepare your workspace
Start by setting up a clean and organised workspace. Sanitise all your utensils and work area to ensure a hygienic environment to make your bath oil. Don’t forget to put on gloves and wear an apron to protect yourself and your formulation. Learn more about setting up your home formulation lab in this blog post.
Step 2: Weigh your botanical oils and emulsifier
Next, set your glass beaker onto your scales and tare them (to do so, simply press the “tare” button). Weigh your castor oil, MCT, plum oil and emulsifier, taring the scales after each ingredient. Mix the blend gently with a glass rod until all ingredients are fully combined.
Step 3: Weigh your essential oils and vitamin E
Now, weigh the essential oils and vitamin E into a watch glass. Then, add them to the beaker containing the oils and stir gently. If you are more experienced, you can add these ingredients directly into your main beaker.
Step 4: Add your natural colourant
Once you’ve stirred your blend, set a watch glass onto your scales and tare them. Weigh the gromwell extract (which naturally colours your bath oil a lovely pink-reddish shade) and then add it to your main beaker. Stir gently until all ingredients are fully combined. Once again, you can weigh the colourant directly into the main beaker if you’re feeling confident.
Step 5: Package and label
Finally, transfer your mixture to a bottle, label and enjoy! To use, your bath oil, simply pour it into your bath water and watch it turn into a luxurious milky solution.
Formulation notes:
This formula is incredibly easy to make and there shouldn’t be any challenges along the way. Just remember 50g of oil does not equal 50ml, so it’s best to use a larger beaker to avoid spills.
As mentioned earlier, the star of this bath oil is PGMO.4, which gives it that magical blooming effect when it meets water. But if you’re curious about alternatives to PGMO.4, I’ve also experimented with a mix of Softfeel PP (INCI: Polyglyceryl-3 Palmitate) at 10% and GMCY (INCI: Glyceryl Caprylate) at 10%. It worked beautifully and delivered similar results, but it required heating to blend properly, which is why I stuck with PGMO.4. However, feel free to experiment! The sky is really the limit with this formula, as it’s endlessly customisable.
And if you’d like to try other natural bath products, why not try making these fun bath bombs?
Customising your bath oil
This blooming bath oil is customisable so you can fully make it your own. Here are a few suggestions on how you can swap and tweak ingredients:
Plant oils
You can easily replace the plant oils with alternatives you prefer or have on hand. Since this bath oil will ultimately go down the drain, I recommend avoiding overly expensive or precious oils for everyday use. However, if you’re making it for a special occasion, feel free to add some more precious oils – but do so mindfully. Here are a few oils you could try:
Top 10 botanical oils every formulator needs
Colourants
The reddish-pink tint in this formulation comes from a specific colourant, but you don’t have to stick to it – or even use a colourant at all! For similar results, you could try alkanet extract for a pink shade or experiment with coloured oils like sea buckthorn or buriti to achieve a warm, orangey tone. Just ensure you use an oil-soluble colourant that blends seamlessly. Here are other ideas of natural colourants you could use:
Essential oils
The essential oils are also entirely customisable, letting you explore different themes or moods. For instance, I’ve tried blends like rosemary and peppermint for a refreshing, invigorating experience.
You can create a version tailored to your preferences or the occasion – making this bath oil as special and unique as you want it to be! Whether you want something calming, uplifting, or energising, the choice is entirely yours. Find more about essential oils below:
Episode 6: Essential oil safety with Robert Tisserand
Ready to start formulating?
I hope you’ll enjoy making this blooming bath oil as much as I did! I’d love to hear about your experience and customisations in the comments below.
And, if you enjoyed this formulation, just imagine what else you could create! Why not take the next step and learn how to make your own organic skincare from home? Check out our FREE mini formulation course to discover just how easy, fun, and empowering it is to create your own products and become an organic formulator.
Join us NOW and start your formulation journey today!
FAQ
- What is a bath oil?
A bath oil is a great addition to your bathtime routine, designed to nourish and moisturise your skin while providing a relaxing sensory experience. The bath oil I created stands out for its transforming texture, turning from an oil blend into a milky solution when it hits the water. Its delightful pink/red colouring and soothing floral scent makes it perfect for special moments – or simply treating yourself.
- How do you use this bath oil?
To use, simply add the desired amount of bath oil to your warm bathwater. As it mixes with the water, it blooms into a milky solution, dispersing evenly, hence the name of the formulation. This oil doesn’t leave any residue in the tub, so you don’t have to worry about that.
- What does it look like, feel like, and smell like?
This bath oil is a slightly viscous, translucent pink/red liquid. It has a soft floral fragrance with calming notes of bergamot, lavender, and ylang-ylang, offering a relaxing and indulgent bath experience.
- How can you customise this bath oil?
This formulation is entirely customisable. You can swap out plant oils and essential oils to suit your preferences and experiment with different colours. Keep in mind that this oil is meant for the bath, so the ingredients will ultimately wash away down the drain, so avoid using all of your precious ingredients in one go.
Suggested suppliers
Many of the suppliers below ship internationally and I’ve included their country or regional base for your convenience.
I found the PGMO.4 at Alexmo, but you can also source Durosoft PG4-0 from Bay House Aromatics and a few other suppliers. While the INCI is the same, there are slight differences in the ingredients. For the gromwell extract, I sourced it from Aroma Zone (it’s called Rouge Grenadine), but you can also find it at Dauphine Organics. Happy sourcing!
Aroma-Zone (EU)
Aromantic (UK)
Alexmo Cosmetics (EU)
Manske (EU)
The Soap Kitchen (UK)
Ellemental (EU)
Lotioncrafter (USA)
Essential Labs (USA)
Go Native NZ (New Zealand)
Naturally Balmy (UK)
O&3 – The Oil Family (UK/EU)
Soap & More (Canada)
Handymade (EU)
FREE TRAINING
Learn how to become an
Organic Skincare Formulator
FREE TRAINING
How to become an
Organic Skincare Entrepreneur
FREE TRAINING
How to become an
Organic Skincare Entrepreneur
Leave us a comment
Beatriz Amaral, a cosmetic scientist worked at Formula Botanica from 2021 – 2025. Read more about the Formula Botanica team.
){kind=link}